1. Field of the Invention
The present invention relates to a camera of a flash built-in type. More particularly, the present invention relates to a camera of a flash built-in type provided with a mechanism for keeping movable a flash emitting unit relative to a camera body.
2. Description Related to the Prior Art
There is a flash built-in type of camera useful in taking an exposure at night or for a rear light scene. For example, U.S. Pat. No. 6,314,244 (corresponding to JP-A 2000-330168) discloses a camera with a flip-up flash device in which a flip-up flash emitting unit is movable for the purpose of protection of the flash emitting unit or preventing a red-eye phenomenon. The flash emitting unit is movable relative to a camera body between a contained position and a flashing position, and when the camera is not used, is moved to the contained position, and when the camera is used, is moved to the flashing position where the flash emitting unit protrudes from the camera body.
To move the flash emitting unit between the contained position and the flashing position, the flash emitting unit is rotated. In the camera having the flash emitting unit being rotatable, an axis of the rotation is disposed at an end sufficiently distant from a flashing surface for the purpose of reducing an amount or rotation of the flash emitting unit between the contained position and the flashing position. The flash emitting unit is biased by a spring or the like toward the flashing position. This is in consideration of possible failure in the movement of the flash emitting unit to the flashing position due to a breakage and the like. Furthermore, a bias mechanism with a spring or the like is used for the purpose of absorbing incidental motion of the flash emitting unit in order to cope with a user s inadvertent push or pull of the flash emitting unit.
JP-A 2001-166362 discloses disabling of flash emission at the time that the flash emitting unit is in the contained position. According to this type of camera, the flash emission is switched on and off by detection of a set position of the flash emitting unit by use of a switch element. Furthermore, a retention of the flash emitting unit in the flashing position suitably determined is also important. It is known in the art that a stopper is formed with the flash emitting unit, and is contacted and retained by the camera body or the like.
U.S. Pat. No. 6,374,051 (corresponding to JP-A 2000-347250) discloses the camera in which a driving source or motor is used for moving the flash emitting unit, and also moving a movable lens barrel between collapsed and photograph-taking positions. Driving force of the motor is suitably transmitted. When a power source is turned on for the camera, the movable lens barrel is moved forwards from the collapsed position. In response to this, the flash emitting unit is moved from the contained position to the flashing position. When the power source is turned off, the movable lens barrel is moved backwards to the collapsed position in the camera. The flash emitting unit moves again from the flashing position to the contained position. A type of the camera is provided with a zoom lens in the movable lens barrel. For this type, the flash emitting unit is linked with the driving source or motor only in a section defined between the collapsed position and a wide-angle end position which is an initial position at the time of turning on the power. The flash emitting unit is unlinked from the motor if the movable lens barrel is in a section from the wide-angle end position to a telephoto end position.
The movable lens barrel in the camera is movable within a first region from the wide-angle end position to the telephoto end position with first stroke, and movable within a second region from the collapsed position to the wide-angle end position with second stroke. Typically in a zoom camera of a somewhat short focal length, the second stroke behind the wide-angle end position is excessively smaller than the first stroke in front of the wide-angle end position. In considering this, it is difficult or impossible to use the linking of the movable lens barrel with the second stroke for the purpose of moving the flash emitting unit by transmitting the driving force.
The flash emitting unit has a considerable weight, and also has stroke being remarkably great in the movement. Also, the stroke and load of the above-mentioned bias mechanism is additionally considered. Therefore, a mechanism for moving the flash emitting unit requires the driving force or the stroke being very great. To enlarge the driving force in the moving mechanism for the flash emitting unit, it is conceived to use the driving source or motor of an enlarged size. However, this is unfavorable because it causes enlargement of the size of the camera.
It is to be noted that increase in the driving force can be conceived on the basis of a greater ratio of reducing the speed of rotation of the driving source or motor. For the purpose of linking of the movable lens barrel and the flash emitting unit, it is necessary to use a rotating element which does not make one rotation even during movement in the entire stroke of the movable lens barrel. Otherwise, it is necessary to use of a straight movable element which does not reach an end position even during movement in the entire stroke of the movable lens barrel. However, the enlargement in the speed reducing factor causes the non-linked region of the rotating element or straight movable element, which cannot be contained in a space of the camera.
A rotatable structure of the flash emitting unit requires a first interface, a stopper and a second interface. The first interface is connected for movement together with the movable lens barrel. The stopper is used for setting in the flashing position in a firm manner. The second interface is for connection with a switch for detecting a position of the flash emitting unit. However, high precision in the operation can be obtained only if those elements are disposed suitably away from a rotational axis of the flash emitting unit. However, those three elements at sufficient distances from the rotational axis of the flash emitting unit enlarges a space for rotation of the flash emitting unit. This is inconsistent with reduction of the camera.